This is a black satin-paneled cocoon pullover shirt from epidemique (エピデミーク). The front is made of satin fabric, and the back is cotton. It has a relaxed fit and can be worn for a clean, elegant look. Image 5 is a reference for the size, and I have borrowed a picture of the white color variation from the shop. I purchased it a few years ago from a select shop for around 9,000 yen. It has been worn infrequently and is in good condition.